diff options
| -rw-r--r-- | block/blk-cgroup.c | 107 | ||||
| -rw-r--r-- | block/blk-cgroup.h | 35 |
2 files changed, 142 insertions, 0 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 3aec4cdc8968..f9797b244eb3 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -32,6 +32,26 @@ EXPORT_SYMBOL_GPL(blkcg_root); static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS]; +static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, + struct request_queue *q, bool update_hint); + +/** + * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants + * @d_blkg: loop cursor pointing to the current descendant + * @pos_cgrp: used for iteration + * @p_blkg: target blkg to walk descendants of + * + * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU + * read locked. If called under either blkcg or queue lock, the iteration + * is guaranteed to include all and only online blkgs. The caller may + * update @pos_cgrp by calling cgroup_rightmost_descendant() to skip + * subtree. + */ +#define blkg_for_each_descendant_pre(d_blkg, pos_cgrp, p_blkg) \ + cgroup_for_each_descendant_pre((pos_cgrp), (p_blkg)->blkcg->css.cgroup) \ + if (((d_blkg) = __blkg_lookup(cgroup_to_blkcg(pos_cgrp), \ + (p_blkg)->q, false))) + static bool blkcg_policy_enabled(struct request_queue *q, const struct blkcg_policy *pol) { @@ -127,6 +147,17 @@ err_free: return NULL; } +/** + * __blkg_lookup - internal version of blkg_lookup() + * @blkcg: blkcg of interest + * @q: request_queue of interest + * @update_hint: whether to update lookup hint with the result or not + * + * This is internal version and shouldn't be used by policy + * implementations. Looks up blkgs for the @blkcg - @q pair regardless of + * @q's bypass state. If @update_hint is %true, the caller should be + * holding @q->queue_lock and lookup hint is updated on success. + */ static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q, bool update_hint) { @@ -586,6 +617,82 @@ u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, EXPORT_SYMBOL_GPL(blkg_prfill_rwstat); /** + * blkg_stat_recursive_sum - collect hierarchical blkg_stat + * @pd: policy private data of interest + * @off: offset to the blkg_stat in @pd + * + * Collect the blkg_stat specified by @off from @pd and all its online + * descendants and return the sum. The caller must be holding the queue + * lock for online tests. + */ +u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off) +{ + struct blkcg_policy *pol = blkcg_policy[pd->plid]; + struct blkcg_gq *pos_blkg; + struct cgroup *pos_cgrp; + u64 sum; + + lockdep_assert_held(pd->blkg->q->queue_lock); + + sum = blkg_stat_read((void *)pd + off); + + rcu_read_lock(); + blkg_for_each_descendant_pre(pos_blkg, pos_cgrp, pd_to_blkg(pd)) { + struct blkg_policy_data *pos_pd = blkg_to_pd(pos_blkg, pol); + struct blkg_stat *stat = (void *)pos_pd + off; + + if (pos_blkg->online) + sum += blkg_stat_read(stat); + } + rcu_read_unlock(); + + return sum; +} +EXPORT_SYMBOL_GPL(blkg_stat_recursive_sum); + +/** + * blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat + * @pd: policy private data of interest + * @off: offset to the blkg_stat in @pd + * + * Collect the blkg_rwstat specified by @off from @pd and all its online + * descendants and return the sum. The caller must be holding the queue + * lock for online tests. + */ +struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd, + int off) +{ + struct blkcg_policy *pol = blkcg_policy[pd->plid]; + struct blkcg_gq *pos_blkg; + struct cgroup *pos_cgrp; + struct blkg_rwstat sum; + int i; + + lockdep_assert_held(pd->blkg->q->queue_lock); + + sum = blkg_rwstat_read((void *)pd + off); + + rcu_read_lock(); + blkg_for_each_descendant_pre(pos_blkg, pos_cgrp, pd_to_blkg(pd)) { + struct blkg_policy_data *pos_pd = blkg_to_pd(pos_blkg, pol); + struct blkg_rwstat *rwstat = (void *)pos_pd + off; + struct blkg_rwstat tmp; + + if (!pos_blkg->online) + continue; + + tmp = blkg_rwstat_read(rwstat); + + for (i = 0; i < BLKG_RWSTAT_NR; i++) + sum.cnt[i] += tmp.cnt[i]; + } + rcu_read_unlock(); + + return sum; +} +EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum); + +/** * blkg_conf_prep - parse and prepare for per-blkg config update * @blkcg: target block cgroup * @pol: target policy diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 586c0ac3309a..f2b292925ccd 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -164,6 +164,10 @@ u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off); u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, int off); +u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off); +struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd, + int off); + struct blkg_conf_ctx { struct gendisk *disk; struct blkcg_gq *blkg; @@ -414,6 +418,18 @@ static inline void blkg_stat_reset(struct blkg_stat *stat) } /** + * blkg_stat_merge - merge a blkg_stat into another + * @to: the destination blkg_stat + * @from: the source + * + * Add @from's count to @to. + */ +static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from) +{ + blkg_stat_add(to, blkg_stat_read(from)); +} + +/** * blkg_rwstat_add - add a value to a blkg_rwstat * @rwstat: target blkg_rwstat * @rw: mask of REQ_{WRITE|SYNC} @@ -484,6 +500,25 @@ static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat) memset(rwstat->cnt, 0, sizeof(rwstat->cnt)); } +/** + * blkg_rwstat_merge - merge a blkg_rwstat into another + * @to: the destination blkg_rwstat + * @from: the source + * + * Add @from's counts to @to. + */ +static inline void blkg_rwstat_merge(struct blkg_rwstat *to, + struct blkg_rwstat *from) +{ + struct blkg_rwstat v = blkg_rwstat_read(from); + int i; + + u64_stats_update_begin(&to->syncp); + for (i = 0; i < BLKG_RWSTAT_NR; i++) + to->cnt[i] += v.cnt[i]; + u64_stats_update_end(&to->syncp); +} + #else /* CONFIG_BLK_CGROUP */ struct cgroup; |